Mandibular permanent second molar with four roots and root canals: a case report.

Although four-rooted mandibular first molars have been observed on a few occasions in the literature, to the best of our knowledge, four-rooted second molars have not been reported. Here, we describe a mandibular second molar with four roots and canals: two mesial and two distal. Mesial roots were separated in the cervical one-third near the cervical margin, while distal roots were divided at a lower level in the middle one-third of the root.

Mutation frequencies of EXT1 and EXT2 in 43 Japanese families with hereditary multiple exostoses.

Hereditary multiple exostoses (EXT) is an autosomal dominant bone disease characterized by the formation of cartilage-capped prominences. EXT is genetically heterogeneous with at least four chromosomal loci. Among the four loci, the exostosis type 1 gene (EXT1) and type 2 gene (EXT2) have been cloned.

Spectra of spontaneous mutations at the hprt locus in colorectal carcinoma cell lines defective in mismatch repair.

Spectra of spontaneous mutations at the hypoxanthine-guanine phosphoribosyltransferase (hprt) locus in colon carcinoma cell lines HCT116 and HCT-15 deficient in mismatch repair and displaying mutator phenotypes were determined. HCT116 and HCT-15 cells, respectively, harbour a mutation in the mismatch repair gene hMLH1 and GTBP. The mutation frequency at the hprt locus in both cell lines was elevated by about two orders, but the microsatellite instability in HCT116 cells was one order higher than in HCT-15 cells.

[192Ir brachytherapy].

Modern high technology has recently brought a precision treatment modality in the field of brachytherapy for cancer patients. Ir-192 manual afterloading (hair pin technique of Ir-192 wire) replaced the technique utilizing Ra-226 needles at our department in 1973. In May 1991, microSelectron-HDR (Ir-192 micro-source of 370 GBq) was installed in Osaka University Hospital.